Defective Epstein-Barr virus specific suppressor T cell function in progressive systemic sclerosis

Detection of Epstein-Barr virus in systemic sclerosis patients: A molecular and serological based study

OBJECTIVE

This study aimed to evaluate an association between Epstein-Barr virus (EBV) and systemic sclerosis (SSc).

METHODOLOGY

One hundred and fifty (138 female, 12 male) consecutive adult SSc patients fulfilling the American College of Rheumatology (ACR)/ European League Against Rheumatism (EULAR) criteria were included in this cross-sectional study. Serological analysis by line blot for class immunoglobulin G (IgG) and IgM antibodies against EBV antigen (EBV capsid antigen [VCA] gp125, VCA p19, EBNA-1, p22, EA-D) and quantification of EBV DNA in whole blood by real-time polymerase chain reaction was performed.

RESULTS

Class IgM antibodies against VCA gp125 (22.8% vs 0%, P < .0002), VCA p19 (55.7% vs 4.4%, P < .0001), EBNA1 (35.7% vs 0%, P < .0001), p22 (24.2% vs 0%, P < .0001), EA-D (14.2% vs 2.2%, P < .04), and class IgG antibodies against p22 (95.7% vs 82.2%, P < .02) and EA-D (54.2% vs 0%, P < .0001) reactivities were significantly higher in SSc patients than in controls. The past infection was significantly associated with the control group (42.8% vs 91%, P < .0001); and the viral reactivation was significantly associated with the SSc group (55.7% vs 4.4%, P < .0001). Only three (2%) out of 150 SSc patients were positive for EBV DNA, similar to the control group (2%) (P > .9).

CONCLUSION

The study shows a strong serological association of EBV (reactivation stage) with SSc patients in the absence of viral DNA in the circulation, indicating the EBV reservoir or tropism presence elsewhere.

Fresh Insights into Disease Etiology and the Role of Microbial Pathogens

Pathogens have been implicated in the initiation and/or promotion of systemic sclerosis (scleroderma, SSc); however, no evidence was found to substantiate the direct contribution to this disease in past years. Recently, significant advances have been made in understanding the role of the innate immune system in SSc pathogenesis, supporting the idea that pathogens might interact with host innate immune-regulatory responses in SSc. In light of these findings, we review the studies that identified the presence of pathogens in SSc, along with studies on pathogens implicated in driving the innate immune dysregulation in SSc. The goal of this review is to illustrate how these pathogens, specifically viruses, may play important role both as triggers of the innate immune system, and critical players in the development of SSc disease.

Update on etiopathogenesis of systemic sclerosis

Systemic Sclerosis (SSc) is an autoimmune disease of multifactorial etiology, triggered by a combination of genetic and environmental factors. Its varied clinical expression results from the complex physiopathogenic interaction of three main elements: proliferative vasculopathy, immune dysregulation and abnormal deposition and remodeling of the extracellular matrix (ECM), of which the characteristic disease fibrosis is the result. Early physiopathogenic events appear to be endothelial injury and imbalance in vascular repair with the activation of endothelial cells, the immune system and platelets, with the release of multiple mediators such as TH2 proinflammatory cytokines and growth factors, triggering a sequence of simultaneous or cascading events that involve several intracellular signaling pathways. The most important result of these events is the hyperactivation of fibroblasts, the main effector cells of fibrosis, which will then produce large amounts of ECM constituents and secrete multiple growth factors and cytokines that perpetuate the process. In this article we review the main factors potentially involved in the etiology of SSc and reexamine the current knowledge about the most important mechanisms involved in the development of lesions that are characteristic of the disease. A better understanding of these physiopathogenic mechanisms will help identify potential therapeutic targets, which may result in advances in the management of this complex and debilitating disease.

The pathogenesis of systemic sclerosis revisited

Although infectiological stimuli, environmental factors and genotypic features are known to contribute to the initiation and perpetuation of systemic sclerosis (SSc), its etiology still remains to be enigmatic, and less elusive insights are to be achieved by ongoing and future investigations. Being characterized, however, as chronic autoimmune disease with excessive collagen accumulation in skin, synovia and visceral organs such as lung, heart, and digestive tract along with obliterating angiopathy, the pathophysiology of SSc can be summarized as being based on imbalances of the cellular and humoral immune system, vascular dysfunction and activation of resident connective tissue cells. A complex interplay between these major components manages to establish and maintain the inability of the vasculature to adequately react to the need for dilatation, constriction and growth of new vessels, to cause the increased deposition of extracellular matrix constituents as well as to facilitate immunological disarrangement. Despite parallels to the chicken and egg causality dilemma, all of these account for what later clinicians observe in patients suffering from Raynaud's phenomenon, digital ulcers, sclerodactyly, rigidity of the face, microstomia, sicca syndrome, dyspnea, dry cough, pulmonary hypertension, palpitations, syncopes, renal insufficiency, dysphagia, gastroesophageal reflux, dyspepsia, generalized arthralgias, but also dyspareunia, or erectile dysfunction.

Serologic response to Epstein-Barr virus antigens in patients with systemic lupus erythematosus: a controlled study

Previous studies showed a link between systemic lupus erythematosus (SLE) and Epstein-Barr virus (EBV) infection. We sought to determine the features of serologic response to EBV in SLE patients and whether this response differs from those of systemic sclerosis (SSc) and primary antiphospholipid syndrome (PAPS) patients as well as healthy individuals. Sera from 198 consecutive SLE patients have been tested to detect IgG antibodies to EA/D, EBNA-1, VCA P18 and for comparison, cytomegalovirus (CMV) using commercially available ELISA kits (Trinity Biotech, USA). Forty-six SSc patients and 38 PAPS patients were enrolled as diseased control groups and sixty-five individuals as healthy controls. Significantly more SLE (54%, P = 0.001, OR 5.77, 95% CI 2.8-11.6), SSc (41.3%, P = 0.005, OR 3.4, 95% CI 1.4-8.2) and PAPS sera (36.8%, P = 0.023, OR 2.86, 95% CI 1.14-7.22) reacted against EA/D than healthy controls (16.9%). The mean age of anti-EA/D-positive SLE patients was significantly higher, and their disease duration was longer compared to anti-EA/D-negative SLE patients (41 ± 14 vs. 33.8 ± 10.8 years, P < 0.001 and 100 ± 73 vs. 71 ± 62 months, P = 0.003). In SLE patients, EA/D reactivity was associated with Raynaud's phenomenon and the presence of any anti-ENA antibodies. Although it did not reach a statistical significance, anti-EBNA-1 reactivity was slightly lower in patients with SLE. The frequency of anti-CMV Ig G positivity was found significantly higher in SLE patients (100%) when compared to patients with SSc (95.7%), PAPS (94.7%) and healthy controls (95.4%) (P = 0.035, P = 0.025 and P = 0.015 respectively). Our results support the proposed link between EBV and SLE. The finding that SSc and PAPS patients also have increased frequency of anti-EA/D response has revealed that this immune interaction may not be unique to patients with SLE, and there may be a common mechanism involving EBV in these autoimmune diseases.

Primary B-cell lymphoma of the tongue in a patient with systemic sclerosis

We report a patient with systemic sclerosis who had the unusual development of a large-cell B-cell lymphoma of the base of his tongue. Patients with systemic sclerosis display an increased incidence of malignant neoplasms, particularly, breast and lung carcinomas [Arthritis. Rheum. 36 (1993) 460; Ann. Rheum. Dis. 52 (1993) 531]. The description of this case adds further evidence to the possible interrelationship of systemic sclerosis and the development of malignant neoplasms. A careful review of the English medical literature disclosed that B-cell lymphoma of the tongue in a patient with systemic sclerosis is an association which has not been described previously.

Abnormalities of T lymphocyte subsets in systemic sclerosis demonstrated with anti-CD45RA and anti-CD29 monoclonal antibodies

T cell subpopulations were assessed by two colour flow cytometry with phycoerythrin conjugated anti-CD45RA and anti-CD29 and fluorescein conjugated anti-CD4 and anti-CD8 monoclonal antibodies, on peripheral blood lymphocytes from 12 patients with systemic sclerosis and from nine control subjects. The percentage of CD4+CD29+ cells was significantly higher in patients with systemic sclerosis than in controls (mean (SEM) 68.8 (3.1) v 47.9 (4.1) respectively). CD4+CD45RA+ cells were not significantly different in patients and controls. CD8+CD29+ and CD8+CD45RA+ subpopulations were significantly higher in patients with systemic sclerosis than in controls (83.0 (3.2) v 58.7 (6.8) and 80.2 (3.0) v 66.9 (3.2) respectively). The increase in the percentage of CD29+ cells suggests an activation of memory cells in patients with systemic sclerosis, which may play an important part in the pathogenesis of the disease.

Normal suppressive T cell function of Epstein-Barr virus induced B cell activation in type 1 (insulin dependent) diabetes mellitus

Several studies have demonstrated abnormalities of T cell regulation of Epstein-Barr virus-induced B cell activation in systemic autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematous, and systemic sclerosis. However, a normal suppressive peripheral T cell function was observed in Graves' disease. To investigate whether this abnormality is a common feature to other autoimmune diseases, we studied T cell regulation of Epstein-Barr virus induced B cell activation in 15 newly diagnosed type 1 (insulin dependent) diabetes mellitus patients and 10 normal control subjects. Peripheral B lymphocytes infected with Epstein-Barr virus were cultured for 20 days in the presence or absence of autologous T cells at different ratios (1:1 and 1:4). IgM and IgG secretions into the supernatants were determined using an enzyme-linked immunosorbent assay. The extent of suppression when T cells were added, as measured by a suppression ratio, was not significantly different in type 1 (insulin dependent) diabetes mellitus patients and normal subjects. We conclude that in type 1 (insulin dependent) diabetes mellitus, the autoimmune reactivity is not dependent upon a generalized suppression defect. It can be hypothesized, therefore, that in type 1 diabetes mellitus as well as in Graves' disease, a local or organ specific suppressor deficit may induce the autoimmune phenomena.

Recombinant interferon-gamma in the treatment of systemic sclerosis

PURPOSE

Recombinant interferon-gamma (IFN-gamma) is a potent and selective inhibitor of collagen production by dermal fibroblasts in vitro and has numerous immunoregulatory activities. We assessed the effects of recombinant IFN-gamma in the treatment of patients with systemic sclerosis.

PATIENTS AND METHODS

Ten patients entered the study and nine completed the six-month study period. Recombinant IFN-gamma was administered once daily for seven days per week by intramuscular injections: 10 micrograms/day for 10 days, 25 micrograms/day for 10 days, 50 micrograms/day for 10 days, and 100 micrograms/day for the next five months.

RESULTS

After the six-month treatment period, a significant improvement, as compared with base-line values, was observed in total skin score, maximal oral opening, range of motion of wrists and elbows, grip strength, functional index, dysphagia, and creatinine clearance. No serious side effects were observed; however, a significant decrease in white blood cell counts and in peripheral blood lymphocytes was noted.

CONCLUSION

These results suggest that recombinant IFN-gamma may be beneficial in the treatment of patients with systemic sclerosis.

Increased proto-oncogene expression in peripheral blood T lymphocytes from patients with systemic sclerosis

The expression of c-myc, c-myb, and c-ras proto-oncogenes, determined using RNA hybridization techniques (slot-blot), was significantly increased in peripheral blood T lymphocytes, but not in B cells, from 17 patients with systemic sclerosis with diffuse scleroderma, compared with the expression in normal control subjects. The magnitude of expression of c-myc and c-myb tended to be higher in patients with early, active disease. These results demonstrate an in vivo activation of T cells from systemic sclerosis patients, which may play an important role in the pathogenesis of the disease.

Impaired late suppression of Epstein-Barr virus (EBV)-induced immunoglobulin synthesis: a common feature of autoimmune disease

We examined regulation of Epstein-Barr virus-induced plaque-forming cell generation in peripheral blood mononuclear cells from several autoimmune and seronegative diseases and correlated these results with Epstein-Barr virus-induced proliferation. We confirmed the defective regulation of Epstein-Barr virus-induced plaque-forming cells in peripheral blood mononuclear cells of patients with rheumatoid arthritis and scleroderma. Peripheral blood mononuclear cells from patients with seronegative arthropathies and chronic infective inflammation (cystic fibrosis) had normal regulation of Epstein-Barr virus-induced plaque-forming cells. Peripheral blood mononuclear cells from rheumatoid arthritis had excessive plaque-forming cell generation in the face of a normally regulated decrease in Epstein-Barr virus-induced proliferation. In contrast, peripheral blood mononuclear cells from scleroderma had defective suppression of both Epstein-Barr virus-induced proliferation and plaque-forming cell generation. Thus, impaired regulation of Epstein-Barr virus-induced plaque-forming cell generation is a common feature of autoimmune disease and demonstrates some specificity for these disorders.

Epstein-Barr virus and human autoimmune diseases: possibilities and pitfalls

Epidemiologic studies suggest that human autoimmune disease involves both genetic and environmental components. Although a great deal has been learned about genetic components (i.e. histocompatibility antigens), little is known about the environmental factors. Because of its ubiquitous nature and ability to stimulate lymphoid responses, Epstein-Barr virus (EBV) has been examined as a potential candidate, particularly in rheumatoid arthritis and systemic lupus erythematosus. No convincing evidence has been produced that it plays a primary etiologic role in these disorders. Nevertheless, EBV or a related herpesvirus may play an indirect role in perpetuating the disorder or in the development of extra-articular manifestations such as Sjögren's syndrome (an autoimmune disorder involving the salivary glands). Current data indicates increased EBV reactivation in some patients with autoimmune diseases, as evidenced by increased viral DNA in their saliva and increased number of circulating B-cells containing EBV in their blood. These patients also have modestly elevated anti-EBV antibody titers and altered antiviral T-cell responses, as measured by the ability to prevent outgrowth of autologous EBV infected B-cells. However, the relevance of these 'abnormalities' to pathogenesis remains unknown. It is hoped that new techniques such as polymerase chain reaction will provide new insights into these questions by allowing detection of viral DNA from tissue biopsies obtained early in the course of disease and by providing a method to identify viral isolates that do not grow well in vitro.

Viruses and salivary gland disease: are there associations?

Viruses can cause sialadenitis and may be associated with other diseases of salivary glands, particularly immunologically mediated and neoplastic lesions. The evidence that such an association with Sjögren's syndrome is causal is reviewed here and shown to be fairly tenuous at present.